1. Field of the Invention
The present invention relates to a silver halide color photographic light-sensitive material, and particularly, to material having an excellent color developable property, a color reproducing property, and an improved finishing stability against variation in the compositions of processing solutions. The present invention also relates to a method for forming color images with such a silver halide color photographic light-sensitive material.
2. Description of the Related Art
In the most common method for forming color images by using a silver halide color photographic light-sensitive material, silver halides are exposed to function as an oxidizing agent, and then an aromatic primary amine color developing agent oxidized by the oxidizing agent and a coupler are reacted to form dyes such as indophenol, indoaniline, indamine, azomethine, phenoxazine, and phenazine. In this method, color images are reproduced by a substrative color process wherein three kinds off dyes for yellow, magenta and cyan are generated In different amounts to form color images.
Conventionally, a 5-pyrazolone coupler has been generally used as a magenta coupler. However, the 5-pyrazolone magenta coupler has a secondary absorbing band in the vicinity of 430 nm. Thus, it has a problem of insufficient color reproduction. To improve color reproduction, pyrazoloazole couplers having an excellent absorbing property have been developed to improve color reproducing properties. For example, the 1H-pyrazolo[5,1-c]-1,2,4-triazole magenta coupler disclosed in U.S. Pat. No. 3,725,067,and the 1H-pyrazolo[1,5-b]-1,2,4-triazole magenta coupler disclosed in JP-B-2-44,051 have excellent absorbing properties. Among them, the 1H-pyrazolo[1,5-b]-1,2,4-triazole magenta is excellent in a color developable property, and fastness of dye images, as well. Especially, couplers wherein a branched alkyl group is introduced into a pyrazolotriazole ring, as described in JP-A-61-65,245 and U.S. Pat. No. 4,882,266, are couplers having improved stability against variable factors in processing, and improved fastness of color images. However, the couplers still have a problem of an unsatisfactory color developable property. The 1H-pyrazolo[1,5-b]-1,2,4-triazole magenta coupler having both of a branched alkyl group at 6- position and a phenyl group at 2- position, which is described in EP-0,571,959 A2,is an excellent coupler having an improved color developable property. However, this coupler has a drawback that, especially when subjected to a quick processing, a tint of magenta is migrated into yellow images, resulting in increased color amalgamation.
Meanwhile, as yellow couplers, a pivaloyl coupler and a benzoyl coupler have been conventionally used. Although the pivaloyl coupler provides excellent image fastness, it has the problems that the molecular extinction coefficient of generated dye molecules is small and that it has low activity as a coupler. Accordingly, a larger amount of the coupler must be used,and thus problem of cost occurs. Also, it is difficult to make a yellow color developable layer thinner. Thus, quicker processing, and reduction of replenishing liquids cannot be achieved.
To increase the extinction coefficient of a dye molecule to be generated, an acylacetoanilide coupler having a cyclic acyl group having 3-5 members (EP-0,447,969 A1), and a marondianilide coupler having a cyclic structure (EP-0,482, 552 A1) have been proposed. Also, many attempts have been made to increase activity of couplers. One of the attempts is to increase activity of a coupler by increasing hydrophilicity of the coupler. For example, JP-A-50-132,926, JP-A-62-206,549, and JP-A-63-291,056 disclose couplers into which oxazolidine-2,4-dione-3-yl, or 1,2,4-triazolidine-3,5-dione-4-yl is introduced as a removable group. Also, JP-A-3-126,939, JP-A-3-126,940, and JP-A-3-126,941 disclose couplers into which imidazolidine-2,4-dion-3-yl is introduced. Meanwhile, studies have been made of yellow couplers to improve an absorption property of generated dyes so as to improve a color reproducing property. The above-mentioned acylacetoanilide coupler having a cyclic acyl group having 3-5 members and the marondianilide coupler having a cyclic configuration are also excellent in the absorption property of dyes. To improve the hue of pivaloyl couplers, the methods have been proposed in which a specific group such as an alkoxy group is introduced into the ortho-position of an anilide ring, as described in JP-A-52-115,219 and JP-A-63-123,047. Also, it has been attempted to improve the color developable property of those couplers, as described in JP-A-3-125,140,JP-A-3-125,141, and JP-A-6-11,808. The color developable property can be improved by increasing hydrohilicity. However, it will increase interaction with a silver halide emulsion agent. Thus, when the light-sensitive material is used after storage for a long period of time, or it is processed with processing solutions whose compositions have been varied, fogging and variation in the gradation occur, bringing new problems. Also, the degree of color amalgamation (wherein a tint of yellow is introduced into magenta images) during processing increases depending on the types of magenta couplers. Especially, when the processing temperature, the concentration of a developing agent and/or pH of a color developing solution is increased, and/or the layers of a light-sensitive material is made thinner for quicker processing, the above-described problems become more serious.